Liquid Bridge

02May

The bridge is made of liquid? Not the magic is not magic, because it can be made with physics. A team of researchers from Austria demonstrated that now we can build a bridge that is composed of the liquid. In these experiments, the team succeeded in demonstrating a bridge composed of pure water that has been distilled three times. They also link the gap, 2.5 centimeters up to 45 minutes, as against the influence of gravity. At first glance this sounds like magic, though clearly only engineering physics. So, what’s your secret?

High Voltage

One of the keys in the experiment is the use of high voltage. The team put pure water that will be the bridge in two glass cups, then a pair of electrodes placed in it. The second glass is placed adjacent but not coincide. Within only a thousandth of a second after the voltage difference of 25 thousand volts is applied through a pair of electrodes, the water in one glass quickly spread to the edges and lightning-quick jump through the gap between the two glasses of glass.

What causes a high voltage is able to catapult water and then jump over the gap and keep the “liquid bridge” is not influenced by the gravitational collapse? Currently no one knows for sure. Nevertheless, some conclusions can already be drawn from the experiment.

Chemically a water molecule H2O is represented by the code. This is because the water molecule consists of two hydrogen atoms (H) and a positively charged oxygen atom (O) are negatively charged. When the pool of pure water is influenced by the electric field, such as high voltage applied to the experiment above, the water molecules will be lined up neatly and hand in hand: the hydrogen atoms are attracted to the negatively charged electrode while oxygen atoms leads to a positive electrode. So far this has been known to apply at the molecular level, but have never been exhibited previously at the macroscopic level as in experiments on liquid bridges.

To test this hypothesis, the same research team then used a glass that had already given an electric charge. It turned out that indeed the electric field of the glass rod capable of making a liquid bridge was changed from straight to curved close to the glass rod.

Water Flowing In Water

Among other measurements are done, the team also measured the variations in fluid density along the “bridge of water” is formed.
They use an optical method commonly called ‘schlieren visualization’. In this method, the dossiers of light is passed perpendicular to the “bridge of water” and then past the edge of a razor-sharp before reaching the light detector. If the fluid density along the bridge were uniform in value, then all the beams of light will pass through the edge of a razor blade and was caught by the detector. However, if there are variations in the density of the liquid on the bridge, that variation will distort and disrupt the way most of the light beam passing through, so the total file that caught the detector is reduced.

With this method, the team from Austria was found that the fluid density is not uniform on the bridge, where the inner side of the bridge is more dense than the outside. In addition, variations in the density of the liquid is not static, but flows from one glass to another. Just as an analogy, you can imagine a co-axial cable (although the analogy is not very accurate because the two phenomena are derived from the laws of physics are different) where the cable in a circle in the flow of electric current in the wire while the outer circle is to help channel the flow of it. Similarly, in the “liquid bridge”, the flowing water molecules are molecules on the inside, while the molecules on the outside was silent and help the flow of molecules in the side of the bridge.

To What Next?

Teams from Austria that wanted to learn in more detail how the actual structure of the molecules that form the “liquid embatan it. For that they are planning a follow-up experiment that would use X-rays.

In addition to answering fundamental curiosity in science, this experiment also have great potential applications. One of them relates to the field of microfluidics, where the liquids with very small volume is controlled with precision and accurately investigated, both for the detection of biological, medical, or environmental.

Currently, there are still many obstacles that need to be solved before a real application can be obtained. One is that the liquid bridge can not survive if the pure water that has been distilled three times was littered with dust and particles. Due to additional charges carried by dust and particles, the liquid bridge that is skipped higher electrical currents.

Temperature on the bridge was also increased, and the bridge will collapse due to the random motion of water molecules to overcome the effects of electrical fields that have been menjajarkannya neatly. However, it is not impossible next experiments will bring surprises and new ideas that will solve the problems above.